def prost(n):
       c = True
       if len(str(n)) != 3:
              c = False
       for d in range(2, int(n ** 0.5) + 1):
              if n % d == 0:
                     c = False
                     break
       return c
dig = {
       "zero": 0,
       "one": 1,
       "two": 2,
       "three": 3,
       "four": 4,
       "five": 5,
       "six": 6,
       "seven": 7,
       "eight": 8,
       "nine": 9}
n = input().split()
if len(n) != 3 or not (set(n) <= set(dig.keys())):
       print("Wrong input")
       exit()
n = dig[n[0]] * 100 + dig[n[1]] * 10 + dig[n[2]]
if prost(n):
       print(n)
else:
       pr = n
       while not prost(pr):
              pr += 1
       pl = n
       while not prost(pl):
              pl -= 1
       if abs(n - pr) >= abs(n - pl):
              print(pl)
       else:
              print(pr)
